It is the purpose of this study to correlate the changes in plasma lipoproteins in animals fed cholesterol-rich diets with the development of accelerated atherosclerosis. The characterization of the lipoproteins induced by cholesterol feeding in dogs, swine, monkeys, rats, and rabbits has established that various species have a similar metabolic response to increased dietary cholesterol. The hyperlipoproteinemia has certain consistent features which include the occurrence of beta-very low density lipoproteins, an increase in low density lipoproteins, and the appearance of a unique lipoprotein, the HDLc. The occurrence in increased concentration of a specific apoprotein (arginine-rich apoproteins) with all these cholesterol induced lipoproteins suggests an important role for this protein in cholesterol metabolism and possibly in accelerated heart disease. BIBLIOGRAPHIC REFERENCES: Mahley, R.W., K.H. Weisgraber, T. Innerarity, and H.B. Brewer, Jr. Characterization of the plasma lipoproteins and apoproteins of the Erythrocebus Patas monkey. Biochemistry. 15:1928, 1976. Mahley, R.W., T.L. Innerarity, K.H. Weisgraber, and D.L. Fry. Canine hyperlipoproteinemia and atherosclerosis: Accumulation of lipid by aortic medial cells in vivo and in vitro. Am. J. Path. 87:205, 1977.